Cooperation between
Fukushima Prefecture and the IAEA
In the Area of Radiation Monitoring, Remediationand Waste Management, Following the
Fukushima Daiichi Nuclear Power Plant Accident(Fukushima Prefecture Initiative Projects)

INTERIM REPORT(2013–2015)(Temporary translation)

2016
Fukushima PrefectureIntroduction
Severe damage was caused by the Tohoku Earthquake that struck on March 11, 2011 and theaccompanying accident at the Fukushima Daiichi Nuclear Power Plant operated by the Tokyo
Electric Power Company. Restoring the environment after this unprecedented nuclear disaster andcreating an environment in which residents of Fukushima Prefecture can live with peace of mind
well into the future have become pressing challenges.
It is critical to gather the wisdom of the world and to work to overcome these challenges, andFukushima Prefecture thus decided to collaborate with the International Atomic Energy Agency(IAEA), which has advanced knowledge in fields concerning nuclear technology. A memorandum ofcooperation between Fukushima Prefecture and the IAEA was signed in December 2012.
According to this memorandum, practical arrangements in the fields of decontamination andradiation monitoring between Fukushima Prefecture and the IAEA were signed on the same date.
(Projects based on these arrangements are referred to as FCPs.)
Following this, additional arrangements were signed for five projects (referred to below as FIPs)
proposed by Fukushima Prefecture in April and October 2013 as a new framework with which toreceive support from the IAEA for projects implemented by Fukushima Prefecture.
The five FIPs are the projects and activities listed below.
1) Survey of radionuclide movement in rivers and lakes2) Survey of radionuclide movement with wildlife
3) Project for studying decontamination technology for rivers and lakes
4) Development of environmental mapping technology using GPS walking surveys
5) Project for the study of promoting the proper treatment of waste containing
radioactive materials at municipal solid waste incinerators
FIPs began in 2013, the year in which the practical arrangements were signed, and it was decided
to publish this interim report because 3 years have passed since.
Fukushima Prefecture has received various forms of support from the IAEA over the 3 years, themajor contents of which are described below.

Contents of major support received from the IAEA
1) Survey of radionuclide movement in rivers and lakes
・Provision of a TODAM (Time-dependent, One-directional, Degradation and Migrational)
model, which is a numerical simulation code of contaminant migration in a river network, for
the quantitative estimation of radionuclides deposited in rivers.
・Technical guidance on the selection of monitoring points and monitoring items, and an
indication of the importance of continuous monitoring at each monitoring point, based on
previous studies for Chernobyl and Mayak.
・Regarding monitoring data obtained by Fukushima Prefecture, advice that measuring Kdvalues and ion concentrations (especially K+ and NH4+) in river water at each monitoring
point is important for the use of numerical models such as the TODAM model.
・Advice on the effectiveness of combining monitoring and models and adding small lakes andmarshes as subjects of research in advancing future research on the dynamics of radioactive
substances in rivers.

22) Survey of radionuclide movement with wildlife
・Provision of foreign literature describing the relationship between wild animals andradionuclides, such as the state of radiocaesium in the muscle tissue of wild animals
including boars and deer in various regions following the Chernobyl nuclear disaster andchanges in radiocaesium levels in the bodies of birds, such as the American gallinule andAmerican wood duck, at the Savannah River Ecology Laboratory.
・Provision of information about the latest scientific results concerning the bioaccumulation ofradiocaesium from experts investigating the relationship between wild animals andradioactive substances.
・Advice on the discussion of study results and data analysis methods, such as the potentialthat mushrooms are the cause of a high radiocaesium concentration in boars of Fukushima
Prefecture, arising from the fact that mushrooms (deer truffles) were found to be the cause ofa high radiocaesium concentration in the muscle tissue of European boars.
3) Project for studying decontamination technology for rivers and lakes
・Provision of information concerning the environmental dynamics of radioactive substancesin rivers, lakes, and marshes of various countries.
・Provision of case studies of environmental remediation measures, such as thedecontamination of radioactive substances in rivers, lakes, and marshes of various countries,
including countermeasures for the inflow of high concentrations of radioactive substances to
the Pripyat River and measures for suppressing the inflow of radioactive substances to theKiev Reservoir.
・Advice on the effective implementation of verification tests targeting riverbeds, including thenecessity of survey items, survey points, and advance simulations for studies confirming
reduced effects of air dose rates and the necessity of survey items (e.g., the size distributionof particles in suspended phases) and weeding test sites when evaluating recontamination.
・Regarding studies of effective radioactive-substance countermeasures targeting river parks,
advice to reference past flooding records when selecting survey sites and advice that thedredging and construction of embankments, as well as grit chambers in upstream basins, areeffective at sites where there is a concern of recontamination.
4) Development of environmental mapping technology using GPS walking surveys
・Provision of information about efforts made by institutions such as the United States
Environmental Protection Agency and Lawrence Berkeley National Laboratory regarding
local radiation dose mapping.
・Advice that inverse-distance weighting (IDW) is more appropriate than Kriging as a meansof interpolation for walking surveys using the GIS, and that considerations must be made forthe shielding effect of buildings and the like.
・Advice to judge measurement conditions of walking surveys by the situation at eachmeasurement point, as it is not always necessary to set uniform measuring conditions.
5) Project for the study of promoting the proper treatment of waste containing
radioactive materials at municipal solid-waste incinerators
・Provision of information on treatment methods employed in other countries for fly ash,3

treatment methods employed in other countries for low-level radioactive waste (i.e.,
incineration, melting treatment of metal, and plasma melting), and instruments for measuring
the concentrations of radioactive substances in waste.
・Technical advice about the incineration of general waste, such as the necessity of studies
conducted from the perspective of the caesium balance of payments, the importance of thecomparative analysis of actual verification test data and model analysis results, and thenecessity of identifying test conditions and assessing waste quality.
・Advice about the importance of countermeasures to the generation of hydrogen fluoride in
the mixed incineration of bag filters (made from Teflon).
・Advice on the necessity of checking the safety (e.g. exposure protection and management) offacility workers.
In this manner, Fukushima Prefecture has implemented FIPs with support from the IAEA. Theinterim report including results of FIPs is provided as follows.
＜This document is issued under the authority and responsibility of the Fukushima Prefecture. ＞

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1. FIP1: Survey of radionuclide movement in rivers and lakes
1.1. Purpose
Fukushima Prefecture has been widely contaminated by radioactive materials owing to an
accident that occurred in 2011 at the Fukushima Daiichi Nuclear Power Station operated by the
Tokyo Electric Power Company. Because river water is widely used for tap water and agricultural
water, it is important to understand the movement of radioactive materials in rivers and to provide
information necessary for the safe use of river water. Additionally, while the effect of redeposition
during floods on the air dose is a concern when radiocaesium flows downstream on particles, it isalso necessary to consider migration through the ecosystem when radiocaesium flows downstream ina dissolved state. It is necessary to grasp the movement of radiocaesium in both its forms. We
therefore studied rivers flowing through Fukushima Prefecture with the purpose of understanding the
dynamics of radioactive materials in rivers, while also aiming for verification of dynamics
forecasting with models based on the monitoring data obtained.
1.2. Methods
In a survey of the Hirose
River Basin (Figure 1(a)), we
established monitoring points
on the Hirose River and its
tributaries from 2013 to
conduct our survey. In the
wide-area
survey,we
conducted
multi-point
surveys of the Abukuma
River System and eight river
systems in the Hamadori area
(Figure 1(b)). At eachmonitoring
point,
we
continuously monitored theturbidity and water level, andcollected suspended sediment
samples with a suspended
sediment sampler.

Figure 1: Map of the locations of monitoring sits and Cs-137
inventory on July 2, 2011(a) Hirose River Basin.
(b) Area subject to a wide-area survey.
* Source: Results of the Third Airborne Monitoring Survey by MEXT (2011)

1.3. Results
The International Atomic
Energy Agency provided us
with the TODAM (Timedependent, One-directional,
Degradation and Migrational)
model, which is a numericalsimulation
codeofcontaminant migration in ariver network, necessary for
implementing
radionuclide
movement forecasting, andwe established a monitoring
Figure 2: Temporal change in the particulate Cs-137
network for collecting data inconcentration at six long-term monitoring sites
the Hirose River Basin. The
particulate
caesium-137
concentration at sites 1–6 in Figure 1(b) decreased to less than one-tenth of the initial values in the 5
years since the accident (Figure 2). The rate of decrease was extremely high compared with the halflife of caesium-137.
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1.4. Conclusion
Thus far, we have collected necessary data for application of the TODAM model and establisheda monitoring network necessary for the verification of dynamics forecasting in the Hirose River
Basin. In the future, we will implement continuous monitoring and conduct numerical modeling forradionuclide dynamics forecasting in the Hirose River Basin using these results. We also performed
a wide-area survey of the Abukuma River System and major rivers in the Hamadori area, and foundthat the concentration of particulate radiocaesium that is adsorbed by small particles and flows
downstream tends to decline. It is important that we continue to accumulate data and continuously
grasp the dynamics of radioactive materials in the wide area.

62. FIP2: Survey of radionuclide movement with wildlife
2.1. Purpose
Owing to the accident at the Fukushima Daiichi Nuclear Power Station, radionuclides, such asradiocaesium, have been found in many wild animals inhabiting the natural environment. Because of
the lack of knowledge concerning the migration of radiocaesium from the environment to wildlife,
we began surveys and research to understand the movement of radiocaesium in the ecosystem.
2.2. Methods(1) Movement of radionuclides with wildlife
We conducted measurements of the caesium-137 concentration contained in the muscles ofwildlife, such as boars and black bears, as well as composition analysis of the stomach contents ofboars and surveys of food that is a high source of caesium for boars.
(2) Home range of wildlife
We surveyed the home range of boars using Global Positioning System (GPS) collars.
2.3. Results(1) Dynamics of radionuclides in wildlifea) Measurement of the concentration of
Boars
gamma-ray-emitting nuclides in thebodies of wildlife
Having compared the caesium-137
concentrations contained in the musclesof boars and black bears, we found that
there is large variation between
individuals among boars but a general
downward trend in black bears; there
are thus different trends depending on
the species of wildlife (Figure 1).
b) Movement of radionuclides into thebodies of wildlife from the environment
Black Bears
We confirmed that the composition of
the stomach contents of boars changes
with the seasons. Although European
research considers the radiocaesium
concentration contained in the musclesof boars to be high because of theirconsumption of fungi, we were unable
to find any pieces of fungi in thestomach contents of boars in the present
research.
c) Form of radiocaesium contained in
Figure 1: Caesium-137 concentration in the muscles
stomach contents
of boars and black bears
Regardingthemigrationof(data period: May 2011–December 2015)
radiocaesium into the bodies of boars,
we are proceeding with surveys toclarify the forms of radiocaesium contained in the stomach contents of boars and the effect ofconsuming soil.
(2) Home range of wildlife
Having surveyed the home range of boars using GPS collars, we found that compared withhome range of boars outside the evacuation area, the home range of boars living inside theevacuation area tended to expand. It is thought that the decline of artificial pressures, such as thedecline due to the evacuation of residents and the decline due to the decline of hunting in theevacuation area, has expanded the home range of boars in the evacuation area.

72.4. Conclusion(1) The concentration of caesium-137 contained in the muscles of wildlife has different trends
depending on the species.
(2) It was confirmed that the stomach content composition of boars changes with the seasons.
(3) It was found that compared with the home range of boars outside the evacuation area, that ofboars living inside the evacuation area tends to expand.

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3. FIP3: Project for studying decontamination technology for rivers and lakes
3.1. Purpose
Because the diffusion of radiocaesium due to the accident at the Fukushima Daiichi Nuclear
Power Plant has caused failures and anxiety in the use and management of rivers and lakes, we havestudied countermeasures by using existing knowledge and implementing surveys.
3.2. Methods(1) Extract countermeasures applicable to Fukushima Prefecture from existing information(2) Tests of decontamination on riversides with limited samples(3) Survey of the state of contamination in river parks, which are lands for public use
3.3. Results(1) Radiocaesium countermeasures considered to be applicable to Fukushima Prefecture
ProblemMedia and Countermeasures

Internal exposure via drinking
waterRivers and lakes: change to alternative sources of drinking water

Immigration of radiocaesium
from irrigation water to crops
and external exposure during
farm work

Rivers and lakes: mitigation of sediment inflow using silt fences, useof the sedimentation function of a dam
Irrigation ponds: silt fences, decontamination of bottom sedimentOverall: potassium fertilization of farmland

Internal exposure via theingestion of aquatic products

Rivers and lakes: restriction of distribution, input of potassium(limited to closed lakes)

External exposure when using
waterside areas (e.g., parks,
roads, and housing)Rivers, lakes, and irrigation ponds (when being drained): access
control, decontamination of floodplains
Rivers: excavation of riverbeds, building of embankments
Irrigation ponds: decontamination of bottom sediment, covering withsand

Common to all problems

Sediment transportation prevention and decontamination of sourceareas of sediment, risk communication(2) Decontamination tests of riversides
Unlike the case for residential and agricultural areas, at riversides where sediment containing
radiocaesium is deposited thickly in part, it has been shown that soil decontamination on the basisof the radiocaesium distribution is effective. After decontamination, there is the possibility ofrecontamination due to flooding, but there was no noticeable silt deposition 6 months after
decontamination, and there was no change in the air dose rate.

Figure1: Air dose rate distribution 1 m above the ground before and after decontamination(Kami-Oguni River, in the Abukuma River System)9

(3) Survey of the state of contamination in river parks
The results of surveying a river park on the Niida River, a major river in the Hamadori region
that has remarkable contamination upstream, show that the air rate dose rate on the riverside was 2
to 3 times that in the surrounding areas. However, heavy rains in September 2015 caused erosion
and the deposition of sediment with a low gamma-ray-emitting caesium concentration, and the air
dose rate decreased to 1.5 times that in the surrounding area. The additional external exposure
dose was estimated at less than 0.1 mSv annually, and it is thus considered that there are no
problems associated with using the river park.
3.4. Conclusion
We organized gamma-ray-emitting caesium countermeasures related to the use of water, andconducted decontamination tests for the purpose of reducing external exposure on a riverside thathas been the subject of a few case studies. Considering also the contamination state of the park, it isadvisable to make a judgment regarding countermeasure policies having comprehensively verified
the spatial distribution and temporal changes in gamma-ray emitting caesium and the exposure dose.

104. FIP4: Development of environmental mapping technology with GPS walking
surveys4.1. Purpose
To grasp the air dose rate (hereinafter,
simply referred to as the dose rate) in
Fukushima Prefecture after the accident at
the Fukushima Daiichi Nuclear Power
Plant, we have measured the dose rate
employing a variety of methods, and we
provide this information on our
homepage.
However, it is difficult to conduct
fixed-point measurements or car-borne
surveys in the alleys of residential areas,parks, or forests. We therefore developed
environmental mapping technology thatuses GPS walking surveys (hereinafter,
simply referred to as walking surveys) to
supplement other forms of monitoring.

Survey meter

Monitoring post, etc.

Car-borne survey

Range where the dose rate can be obtained with car-borne surveys and fixed-point measurements
Range of walking surveys

Figure1: Measurement range of walking surveys

4.2. Methods(1) Development of equipment
We used KURAMA-II, which was developed by
Kyoto University, for walking surveys. KURAMA-II
is a system that can combine data obtained from aradiation detector and GPS device to map dose rates.
We used a high-precision GPS device and stored theequipment in a backpack as a configuration that is
appropriate for walking surveys.
(2) Gathering parameters necessary for walking surveys
Because the contribution of radiation sources
varies depending on the direction in walking
surveys, owing to obstruction by the measurer
Picture1: Image of a walking survey
himself or herself, we confirmed the direction
characteristics.
To decide the correction factor employing comparative tests with survey meters, we used thedose rate measured 1 m above ground by a NaI (Tl) survey meter, whose traceability has been
established as the most certain, and compared that dose rate with the measurement obtained inwalking surveys.
4.3. Results
Results for the direction characteristics indicate that the effect of direction characteristics on
measurements of walking surveys is weak. Additionally, in our comparison with NaI (Tl) survey
meters, we found that it is necessary to use different detectors for low and high dose rates with 1µSv/h as the dividing line. In light of this, we set the correction factor as 1.3 when using a low-doserate detector and 1.1 when using a high-dose-rate detector.
4.4. Conclusion
Certain results have been achieved in the development of walking surveys by 2015, making it
possible to measure the dose rate in a walking survey.

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5. FIP5: Project for the study of promoting the proper treatment of waste
containing radioactive materials at municipal solid-waste incinerators
5.1. Purpose
We conducted demonstration tests at operating incineration facilities to study the immigration
behavior of radiocaesium to bottom ash and fly ash, and to confirm the effectiveness of methods ofcontrolling this radiocaesium migration, as well as technologies that remove radiocaesium in theincineration ashes or make radiocaesium in ashes less soluble. All information and technologies
obtained will be used for the safe and proper disposal of incineration ash (i.e., bottom ash and flyash).
We also observed the effects of the coincineration of used filter cloth of bag filters generated by asolid-waste incineration facility with municipal solid waste (MSW). We focused on the change in theradiocaesium distribution to bottom ash and fly ash, and the effects of coincineration on the facility
and environment.

Figure 1: Issues in the waste combustion process and test study

5.2. Methods(1) Distribution of radiocaesium to bottom ash and fly ash
・Tests for different combustion temperatures
We compared the distributions of radiocaesium to bottom ash and fly ash when the
combustion chamber outlet temperature was raised or lowered 50° C from normal operation,and observed the effect of the temperature change on radiocaesium migration behavior.
・Continuous sampling tests
We continuously sampled bottom ash and fly ash during normal operation, and observed therelationship between the combustion temperature and the migration of radiocaesium to bottom
ash and fly ash.
・Tests confirming the effects of a radiocaesium evaporation accelerator and inhibitor
We sprayed radiocaesium evaporation accelerator (hydrated lime) or inhibitor (bentonite) on
waste fed into a hopper and observed the effects.
(2) Proper treatment of filter cloth covered in fly ash containing radiocaesium
・Used bag filter cloth coincineration tests at solid-waste incinerator facilities
In two facilities having different filter cloth materials, we conducted coincineration tests
12while changing the used filter cloth input ratio and input intervals, and observed the effect on
the radiocaesium distribution to bottom ash and fly ash, the exhaust gas, the facility, theenvironment, and the state of waste combustion.
(3) Understanding radiocaesium leaching characteristics of bottom ash and fly ash
・Leaching tests of bottom ash and fly ash
We conducted leaching tests on bottom ash and fly ash sampled from six solid-waste
incineration facilities in Fukushima Prefecture, and surveyed the leaching characteristics ofradiocaesium.
5.3. Results(1) Distribution of radiocaesium to bottom ash and fly ash
Although a greater radiocaesium distribution to fly ash was observed with the addition of
hydrated lime as a volatility accelerator, we were unable to confirm the reproducibility of thisbehavior. No clear relationship was confirmed between the combustion temperature and themigration behavior of radiocaesium.
(2) Proper treatment of used bag filter cloth adhered with fly ash containing radiocaesium
We confirmed that if the coincineration ratio is set properly, the coincineration of used bag filter
cloth with MSW has no meaningful effect on the radiocaesium distribution to bottom ash and fly
ash, the exhaust gas, the facility, the environment, or the state of waste combustion.
(3) Understanding radiocaesium leaching characteristics of bottom ash and fly ash
We confirmed a generally recognized trend that fly ash has a fairly high radiocaesium leachingrate while bottom ash has a low leaching rate.
5.4. Conclusion
We conclude that a safe and proper coincineration of used bag filter cloth and MSW can beachieved with a proper setting of the coincineration rate.
Regarding the relationship among the combustion temperature, the addition of chemicals, and theradiocaesium distribution to fly ash, very real problems such as a lack of clear reproducibility of theresults remain unsolved.

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